The thylacine is an believed-to-be-extinct marsupial that lived in Australia and surrounding areas. Its color was sandy yellowish-brown to grey. It had 15 - 20 stripes on its back from its shoulders to tail. Its head looked like a dog but its legs and tail were short. Its hair was also short. It had short ears as well.

Thylacines had large, powerful jaws that could open wider than wolves or dogs. They had 46 teeth.

The thylacine was a marsupial. Females had a back-opening pouch. They had up to 4 pups which stayed with the mother until half-grown.

Thylacines were carnivorous and ate kangaroos, other marsupials, small rodents and birds. They also ate sheep and poultry that were introduced from Europe.

They lived in Australia, Papua New Guinea and Tasmania. Its last known location is Tasmania where it has not been seen since the 1950's so it is believed to be extinct. Still, some people believe it still exists in very small numbers.

It is not known why their population declined, however it is most likely due to hunting by humans and the introduction of dogs and competition with the dingo.

Photos and even video exist of the thylacine from the early 1900's. These along with bones, skins and fossils are the only known proof of their existence.

Steller's Sea Cow is an extinct sea mammal. It was related to the manatee and dugongs but was much larger. They grew up to 7.9 meters (25.9 ft) long and weighed up to three tons. It looked like a seal but had two stout forelimbs instead of flippers and a tail like a whale. It's skin was black and thick and its head was very small compared to its body. It had no teeth, but did have two flat white bones. The sea cow was reported to be tame and ate kelp and algae.

It used to live in the Bering Sea and was discovered in the Commander Islands in 1741 by the German naturalist Georg Steller. Fossil records show that they used to live as far South as California and Japan.

Steller's Sea Cow was hunted to extinction by humans by 1768. Although, when discovered by Stellar it is believed that there were only 1500 left. Some speculate that the loss of their algae food source contributed to their extinction.

There are no photos of the sea cow, only drawings, fossils and bones are proof of their existance.

Zebras are odd-toed ungulates like horses and rhinoceroses. An ungulate is an animal with hooves (deer, giraffes, antelopes, horses, zebras and rhinoceroses). Zebras have very good eyesight and sense of smell. They are able to run very fast.

Zebras are black and white. Their black and white stripes help them to hide in tall grass and open dry plains.

The black stripes on zebras have an extra layer of fat. Their black stripes can get up to 18 F (10 C) hotter than their white stripes.

Zebras reach around 53 inches tall and weigh 500-700 pounds. They are resistant to diseases that affect cattle and zebras usually look well-fed even under poor conditions.

Baby zebras have shorter necks and long legs. They are born with long, furry hair and their black stripes are initially brown.

Zebras are found in Africa. They live in savannahs, plains and near mountains. There are 3 types of zebras: Plains, Grevy and Mountain zebras. Plains Zebras are not endangered or threatened, but the Grevy and Mountain Zebras are because their habitats are disappearing and they are over-hunted by humans.

Zebras can live up to 40 years old in captivity. In the wild their lifespan is much shorter.